Joseph



Patented sept. 13,1881.`

IIIII (NoMoael.)

J. C. GITHENS.

ROCK DRILL.

JOSEPH O. GITHENS, OF NEV7 YORK, N. Y., ASSIGNOR TO THE RAND DRILL PATENT OrrrcnV COMPANY, OF SAME PLACE.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 246,947, dated September 13, 1881.

ApplicatonledJulylG, 188,1. (Nomodel.)

To all whom 'it may concern Be it known that LJosnPH C. GITHnNs, of the city and State oi' New York, have invented acertain Improvement in Rook-Drills, of which the following is a specification.

My improvementrelates to that class ofrockdrills in which a spiral bar is employed to impart the rotating feed to the drill, and in which the backward rotation of the spiral bar is prevented by the engagement oi' detent-pawls with a ratchet-wheel applied to the upper end of the spiral bar.

As heretofore constructed the upper portion of the spiral bar is turned down and provided with a male screw-thread and inserted through the ratchet-wheel, and anut is screwed onto it to hohl the ratchet-wheelin place. In operation the constant jarring of the machine lends to loosen and unscrew this nut, and thereby let the spiral bar slip down into the cylinder.

lt is the object of my invention to overcome this difliculty, and l accomplish this object hy forming a laterally-projecting head upon the upper end of the spiral bar, and by boring a hole through the ratchet-wheel ot' the same diameter as the shank of the spiral bar. ln assembling these parts iu the machine the ratchet-wheel is placed in a chamber to the walls of which the detent-pawls are pivoted, and the shank of the spiral bar is dropped through the ratchet-wheel and through a suitable perforation in the chamber containing the ratchet-whee1, until the head ofthe spiral bar rests upon the ratchet-wheel. The ratchet-wheel is prevented from turning on the spiral bar by a key insertedin a key-seatforined partly in the ratchet-wheel and partly through the head and longitudinally along a portion ot' the shank ofthe spiral bar. A cap is then bolted to the ratchet-wheel chamber, and the result is that there can be no detachment of the ratchet-wheel from the spiral bar except by taking the machine apart.

The accompanying drawings, representing a portion of a rock-drill embodying my invention, are as follows:

Figure l is a central longitudinal section of the drill-cylinder, showing the piston, the

spiral bar, and the ratchet-wheel and the ratchetwheel chamber. Fig. 2 is an end View of t-he ratchet-wheel chamber, with the cap or cover removed.

The drawings represent so much of a rockdrill as is necessary for the purpose of illustrating the manner of applying my improvement.

The steam-cylinder A is provided with the usual piston, B, containing at its upper end thel nut C, which engages the spiral bar D.

The ratchet-wheel E is keyed fast to the spiral bar by the key c, and is prevented from turning, except in one direction, by the detent-pawls F F, pivoted to the walls of the ratchet-wheel chamber G. The ratchet-wheel has a hole, c', bored centrally through it ot' the same diameter as that of the shank d of the spiral bar` The key c is seated partly in the key-seat @2in the ratchet-wheel and partly in the channel d formed longitudinally in the spiral bar. The upper portion of the spiral bar, which projects through the ratchet-wheel, is enlarged to form the head d2, which bears upon the surface of the ratchet-wheel, and hence holds the spiral bar so that it cannot slip through the ratchet-wheel into the cylinder. The channel d extends through the head d2 to permit the insertion ot' the key c. A cap, g, is bolted to the ratchet-wheel chamber when the parts have been assembled, as shown.

The machine is provided with the usual longitudinal feed-screw, H, and the other usual appurtenances ot a rock-drill.

The rotating feed of the drill is effected in the usual manner by the action of the spiral bar upon the nut O, screwed to the upper end of the piston, which causes the piston to rotate during its upward movement, because the detent-pawls prevent the spiral bar from backward rotation. During the downward movement of the piston the spiral bar is rotated in the direction in which it is free to move, and thereby is set in position to impart further rotation to the piston during its next upward movement.

I claim as my invention- In a rock-drill, substantially such as described, a spiral bar foriinparting the rotating walls of the chamber or recess in which the feed to the drill, laterally enlarged at its upratchet-Wheel is placed, substantially as and per end and thereby provided with a head, l for the purpose set forth.

in combination with a ratchet-wheel through JOSEPH C. GITHENS. which the shank of the spiral bar is inserted Witnesses:

and upon which the head of the bar bears, ASA FARB,

and a detent pawl or pawls pivoted to the GRACE G. PIKE. 

